Table of Contents
Advertisement
Quick Links
C
D A
L ASS
UDIO
1. Kit Contents
The Si824x Class D Audio Amplifier Reference Design Kit contains the following items:
Audio Class D Amplifier reference design board featuring:
Si8241 ISOdriver
Si8410 Digital Isolator
2. Introduction
This User's Guide discusses the Silicon Labs Audio Class D amplifier reference design, a stereo, two-state, half-
bridge Class D amplifier leveraging the performance advantages of the Si8241 ISOdriver. This two-channel Class
D Audio Amplifier delivers 120 W per channel into 8 , while enabling < 0.02% THD at 60 W and > 95 dB SNR.
High-power audio systems are adopting digital audio technology and evolving toward lower-power, "green"
products that meet Energy Star™ guidelines. Class-D audio systems have started penetrating the high-end
markets where low noise, extremely good THD performance, and very high output power are required in consumer
and industrial applications. The Si824x audio driver family consists of single-chip, isolated, Class-D gate drivers
powering audio systems delivering from 30 W up to 1000 W of audio power.
Occasionally, a new IC is introduced that challenges the current technological hegemony. With features that make
these products the perfect drivers for Class D amplification, the Silicon Labs Si8241/44 Audio Gate Drivers
represent a new standard for the Class D amplifier industry. Based on Silicon Labs' proprietary isolation
technology, the Si824x audio drivers incorporate input-to-output isolation that enables level-translation of signals
without additional external circuits. The Si824x audio drivers feature adjustable dead-time control for achieving
optimal THD, overlap protection that safeguards against shoot-through current damage, robust immunity to latch-
up and high-voltage transients, and lower BOM costs and PCB footprints compared to non-isolated gate drive
solutions. A typical audio driver application using the Si824x is shown in Figure 1. For more information on the
Si824x audio driver, refer to the Si824x datasheet at www.silabs.com/audio.
Figure 1. Si824x-Based Class D Audio Driver Block Diagram
Rev. 0.2 11/10
A
R
MP LIF IE R
EF ERENCE
Copyright © 2010 by Silicon Laboratories
S i 8 2 4 x C l a s s D - K I T
D
E S I G N
U
'
G
S E R
S
U ID E
Si824xClassD-KIT
Advertisement
Table of Contents
Summary of Contents for Silicon Laboratories SI824XCLASSD-KIT SI8241
- Page 1 Rev. 0.2 11/10 S i 8 2 4 x C l a s s D - K I T EF ERENCE E S I G N Copyright © 2010 by Silicon Laboratories ’ S E R U ID E Si824xClassD-KIT...
- Page 2 Si824xClassD-KIT 3. Hardware Overview and Demo 3.1. Reference Design Board Architecture The Silicon Labs Class D reference design architecture uses a phase-shift, self-oscillating modulation approach that is capable of achieving far greater signal-to-noise ratio than clock driven amplifiers (see Figure 2). This self- oscillating implementation eliminates the circuitry necessary to generate the triangle waveform.
- Page 3 3.3. Powering up the Class D Amplifier and Playing Music After the audio source, audio Y-cable, supplies, and speakers have been properly connected as shown in Figure 3. 1. Turn on the ±12 V supplies. 2. Then, turn on the ±50 V supplies. Notice that LED1 should turn on for about 1 sec and then turn off. This on and off sequence clears any overcurrent protection faults and indicates to the user that the amplifier is ready to amplify the audio input signal.
- Page 4 Si824xClassD-KIT 4. Additional Features and Architectural Considerations 4.1. Gate Drive Structure Figure 5 illustrates the ease with which the Si8241 can drive a two-state, half-bridge class D amplifier. The boot supply tied to D1 must be 12 V higher than the –50 V reference (–38 V) so that the MOSFETs each have a 12 V drive signal.
-
Page 5: Undervoltage Protection
RSENSE To High Side MOSFET Figure 6. Over Current Protection Circuit 4.5. Undervoltage Protection The undervoltage protection comparator monitors the positive bus voltage and releases the undervoltage lockout when the voltage is above 37 V. The amplifier starts up after a one-second delay. Note that the red LED remains lit when the amplifier is in shutdown mode and turns off when the amplifier is enabled. - Page 6 Si824xClassD-KIT 5. Si8241-Based Class D Amplifier Connection Description The Si8241-based Class D Amplifier has two Si8241 ISOdrivers and two Si8410 digital isolators installed. Refer to Figure 7 for the locations of the various I/O connectors and major components. Relevant user connection points are detailed below.
- Page 7 Si824xClassD-KIT 6. Schematics Rev. 0.2...
- Page 8 Si824xClassD-KIT Rev. 0.2...
-
Page 9: Bill Of Materials
7. Bill of Materials Table 1. Si824x Class D Audio Amplifier Reference Design Bill of Materials Description 1 µF, 25 V, X5R, C1, C2 0805 Ceramic Capacitor 1 µF, 16 V, 3216 C3, C4 Tantalum Capacitor C24–C27, 0.1 µF, 50 V, X7R, C29, C30, 0603 Ceramic C37–C44... - Page 10 Si824xClassD-KIT Table 1. Si824x Class D Audio Amplifier Reference Design Bill of Materials (Continued) Description 82 µF, 63 V, KZE C67–C70 Series Electrolytic 0.1 µF, 100 V, X7R, C71–C74 1206 Ceramic Capacitor 0.01 µF, 100 V, C75–C78 COG, 1206 Ceramic Capacitor 0.47 µF, 250 V Film C79, C80...
- Page 11 Table 1. Si824x Class D Audio Amplifier Reference Design Bill of Materials (Continued) Description IC Comp Grnd-sens- IC19, IC20 ing LowPwr 8SOIC Isodriver Narrow IC21, IC22 Body J1–J7 1/4 inch-Faston 3 Pin Conn Header Conn RCA Jack J9, J10 Metal R/A YEL PCB JP1–JP3 Jumper L1, L2, L35...
- Page 12 Si824xClassD-KIT Table 1. Si824x Class D Audio Amplifier Reference Design Bill of Materials (Continued) Description 12.1 k, 2010 1% R16, R17 SMT Resistor R18, R21, 20 k, 0603 1% SMT Resistor 4.99 k, 0603 1% R29, R30 SMT Resistor R23, R24, 100 k, 0603 1% R39, R40 SMT Resistor...
- Page 13 Table 1. Si824x Class D Audio Amplifier Reference Design Bill of Materials (Continued) Description Insulator Mica Insulator .860X.520" .141" TO-220 Hdwr Mtg Screw TO- Screw 220CASE 4/40 THR Hdwr Mtg Screw 1/ Screw 4" 4/40 , PCB L- Bracket Mount Lock Hdwr Mtg Lock- Washer...
-
Page 14: Ordering Guide
Si824xClassD-KIT 8. Ordering Guide Ordering Part Number Si824xClassD-KIT Type Audio Class D Amplifier reference design kit using Si8241BB-B-IS1. Rev. 0.2... -
Page 15: Document Change List
OCUMENT HANGE Revision 0.1 to Revision 0.2 Updated Table 1, “Si824x Class D Audio Amplifier Reference Design Bill of Materials,” on page 9. Si824xClassD-KIT Rev. 0.2... -
Page 16: Contact Information
Silicon Laboratories products are not designed, intended, or authorized for use in applications intended to support or sustain life, or for any other application in which the failure of the Silicon Laboratories product could create a situation where per- sonal injury or death may occur.
Need help?
Do you have a question about the SI824XCLASSD-KIT SI8241 and is the answer not in the manual?
Questions and answers